Audio HAL: add channel mask and tags to track metadata

Add channel mask and audio attributes tags to playback
and record track metadata sent to audio HAL.

Bug: 168751366
Test: make
Change-Id: I06a63963e1be53bd965792dec607fa67a89f28bf
diff --git a/services/audioflinger/TrackBase.h b/services/audioflinger/TrackBase.h
index 01d5345..38dab5b 100644
--- a/services/audioflinger/TrackBase.h
+++ b/services/audioflinger/TrackBase.h
@@ -253,6 +253,8 @@
     // Called to tally underrun frames in playback.
     virtual void tallyUnderrunFrames(size_t /* frames */) {}
 
+    audio_channel_mask_t channelMask() const { return mChannelMask; }
+
 protected:
     DISALLOW_COPY_AND_ASSIGN(TrackBase);
 
@@ -278,8 +280,6 @@
 
     size_t frameSize() const { return mFrameSize; }
 
-    audio_channel_mask_t channelMask() const { return mChannelMask; }
-
     virtual uint32_t sampleRate() const { return mSampleRate; }
 
     bool isStopped() const {